The correct answer to this open question is the following.
Using the RACE model, we can say the following.
Restate.
It is true that Nationalism is the desire of one country to put its interest first.
Answer
The Christmas Truce went against that because in the winter of 1914, soldiers from Great Britain, France, and Germany, put a halt to World War hostilities during Christmas. Indeed it was a truce.
Cite.
Historians document that in those Christmas days of 1914, soldiers from the above-mentioned nations exchanged food, had decent conversations, and some souvenirs.
Explain
The ceasefires along the Western Front of WWI in that specific period of time was the result of the goodwill of the soldiers who considered that Christmas was a time to put aside differences, and decided to spend some moments of peace and getting along with each other. It is said that they even play soccer matches.
That is why nationalistic interests were forgotten during those unforgettable days of peace.
